I have a Mauser 25-06. I can remove the bolt and it slides back and forth. However It seems to "hang up" and can be difficult to load and unload shells. I I cleaned and oiled it but I am still having trouble. I am not that familiar with it. Any suggestions?

This is most probably a custom made rifle with a tight reamed chamber. If you are using handloads, try bumping the shoulder of the case back a tad before reloading. Make up a dummy case first and see if this helps.

You don't fully describe the difficulty, so this is just a stab at the problem.

Explain in a bit more detail please. Is the hang up occurring in the magazine or the chamber? What model Mauser? What was the original cartridge?

~ Shells are supposed to feed from the magazine...not just just dropped into the port.
~ The receiver on the Mauser has cuts that control feeding. Modern rifles use the magazine to control feeding, not the receiver. It's possible the alterations were never made from the original cartridge configuration.
~ Extractor may be damaged or incorrectly fit.
~ May be a weak magazine spring.
~ It might be "cock-on-closing" and not really hanging up.

It occurs with or with out shells in it. When I slide the bolt all the way back and then try to close it about half way it starts to get hard to slide and either stops or slides in the rest of the way ( with difficulty)
Hope this gives you a better Idea
I don't use hand loads shells

It occurs with or with out shells in it. When I slide the bolt all the way back and then try to close it about half way it starts to get hard to slide and either stops or slides in the rest of the way ( with difficulty)
Hope this gives you a better Idea
I don't use hand loads shells

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A quick follow up on my last post question. I had two Mausers come in to the shop, a 98 and aVZ 24. The 98 had a bent ejector lever, made it stick binding on the bolt forcing the extractor against the right lug rail in the receiver, just about half closed; the 24 had a broken ejector spring resulting in the same scenario. This is not uncommon with non-matching bolt/receiver #'s and occurs when the bolt is drawn fully to the rear(lotsa slop there). Just a thought.